AMR technology used in conjunction with utility meters, and particularly water meters, must generally operate in relatively harsh environments. For example, water meters and AMR components placed in water meter pits are exposed to high humidity levels almost constantly. Additionally, meters and associated components placed into pits are potentially subject to corrosion due to contact with various corrosive liquids. Often designers try to design the meter components from materials that are capable of withstanding exposure to moisture and/or corrosive liquids. Another option is to hermetically seal the housings containing any electronic components, though this is often not a desired approach because of manufacturing constraints and high costs. Still another approach is to try to insulate any electronic components associated with utility meters from harsh environments through the use of various encapsulants or potting materials.
In cases where electrical components are located in harsh environments, a method for coating or encasing electronics with a potting material or encapsulant with a decreased diffusion rate that corresponds with improved moisture protection and shields the components from corrosive liquids is thus desired. While silicones, polyurethanes, and epoxies have been developed as potting materials and can provide some protection against moisture, thermal shock, and vibration, such potting materials/encapsulants still allow for the penetration of moisture over time due to their higher permeability and diffusion rates. Thus, these materials do not sufficiently waterproof the electrical components that they surround.
Prior publications that describe potting materials or encapsulants include U.S. Pat. No. 7,999,016 to Osada et al. disclosing a “Semiconductor Encapsulating Epoxy Resin and Semiconductor Device,” U.S. Pat. No. 7,763,673 to Okamoto et al. disclosing a “Curable Composition Containing a Silicon-Containing Group Polymer, a Titanium Chelate, and an Amide Wax,” U.S. Pat. No. 7,741,388 to Murotani et al. disclosing an “Epoxy Resin Composition and Semiconductor Device,” U.S. Pat. No. 4,977,009 to Anderson et al. disclosing “Composite Polymer/Dessicant Coatings for IC Encapsulation,” and U.S. Patent Application Publication No. 2010/0067168 by Summers et al. disclosing “Composite Organic Encapsulants.” The complete disclosures of such patent publications are fully incorporated herein by reference for all purposes.
While various methods have been developed for potting or encapsulating electronic components, and while some level of protection from harsh environments has been provided, no particular method of dispensing an encapsulant composition onto electronic components has emerged that encompasses all of the desired characteristics as hereafter presented in accordance with the subject technology.